Advanced Biotech Miscellaneous
- Identify the correct statement for the ‘HAT medium’
(P) Includes drug aminopterin to block major pathway for synthesis of deoxyri-bonucleotides
(Q) Hypoxanthine is precursor for thymidine
(R) Includes drug aminopterin to block major pathway for synthesis of polypeptides
(S) Cells can grow in presence of aminopterin only if they have enzymes thymidine kinase and hypoxanthine-guanine phosphoribosyl transferase
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STATEMENT P : HAT Medium (hypoxanthine-aminopterin-thymidine medium) is a selection medium for mammalian cell culture, which relies on the combination of aminopterin, a drug that acts as a powerful folate metabolism inhibitor by inhibiting dihydrofolate reductase, with hypoxanthine and thymidine which are intermediates in
DNA synthesis. Aminopterin blocks DNA de novo synthesis.
STATEMENT S : The thymidine present in the HAT medium that can be absorbed by the cells and phosphorylated by thymidine kinase (TK) into TMP. By additional phosphorylation reactions, TMP can be used to make thymidine triphosphate (TTP), one of the four nucleotide precursors that are used by DNA polymerases to create DNA. Hypoxanthine-guanine phosphoribosyltransferase (HGPRT) reacts with hypoxanthine absorbed from the medium with PRPP, liberating pyrophosphate, to produce IMP(Inosine Mono Phosphate) by a salvage pathway.
Therefore, the use of HAT medium for cell culture is a form of artificial selection for cells containing working TK and HGPRT.Correct Option: B
STATEMENT P : HAT Medium (hypoxanthine-aminopterin-thymidine medium) is a selection medium for mammalian cell culture, which relies on the combination of aminopterin, a drug that acts as a powerful folate metabolism inhibitor by inhibiting dihydrofolate reductase, with hypoxanthine and thymidine which are intermediates in
DNA synthesis. Aminopterin blocks DNA de novo synthesis.
STATEMENT S : The thymidine present in the HAT medium that can be absorbed by the cells and phosphorylated by thymidine kinase (TK) into TMP. By additional phosphorylation reactions, TMP can be used to make thymidine triphosphate (TTP), one of the four nucleotide precursors that are used by DNA polymerases to create DNA. Hypoxanthine-guanine phosphoribosyltransferase (HGPRT) reacts with hypoxanthine absorbed from the medium with PRPP, liberating pyrophosphate, to produce IMP(Inosine Mono Phosphate) by a salvage pathway.
Therefore, the use of HAT medium for cell culture is a form of artificial selection for cells containing working TK and HGPRT.
- Multiplication of genetically identical copies of a cultivar by asexual reproduction is known as
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By clonal propogation or micropropagation thousands of plants can be produced from a single piece of plant tissue explant. They are genetically identical.
Correct Option: D
By clonal propogation or micropropagation thousands of plants can be produced from a single piece of plant tissue explant. They are genetically identical.
- Parthenogenetic embryos in plants are those which are formed by
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Parthenogenesis is a form of asexual reproduction in which growth and development of embryos occur without fertilization. In plants, parthenogenesis means development of an embryo from an unfertilized egg cell, and is a component process of apomixis.
Correct Option: A
Parthenogenesis is a form of asexual reproduction in which growth and development of embryos occur without fertilization. In plants, parthenogenesis means development of an embryo from an unfertilized egg cell, and is a component process of apomixis.
- A RNA polymerization assay was performed using 3H UTP as the labelled nucleotide with a specific activity of 500 µCi/ µmol (1 µCi = 2.2 × 106 counts per min). After 10 min incubation, the trichloroacetic acid-insoluble radioactivity was found to be 692521 counts per min as determined in a liquid scintillation counter working at 60% efficiency for 3H. The amount of UTP incorporated into the RNA will be
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Since 60% → 692551 cpm
So, 100% = 1154201.67% cpmNumber of moles of 3H UTP = 1154201.67 cpm × μ mol 500 × 2.2 × 106 cpm
= 1050 × 10–12 mole
= 1.05 nmole
There is some error in options. Correct Option: E
Since 60% → 692551 cpm
So, 100% = 1154201.67% cpmNumber of moles of 3H UTP = 1154201.67 cpm × μ mol 500 × 2.2 × 106 cpm
= 1050 × 10–12 mole
= 1.05 nmole
There is some error in options.
- Match the products in Group 1 with their possible applications in Group 2:
Group 1 Group 2 P. Erythropoietin 1. Blood clot Q. Anti-fibrin 99 2. Binding and transport of iron R. Collagenase 3. Anaemia S. Transferrin 4. Animal cell separation
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⚈ Erythropoietin (EPO) is a hormone that prevents anemia (low blood count) by making red blood cells. Anemia causes fatigue and low energy levels. It occurs when there are not enough red blood cells to carry oxygen from the lungs to supply all the body’s needs. Erythropoietin has its primary effect on red blood cells progenitors and precursors by promoting their survival through protecting these cells from apoptosis.
⚈ Anti-fibrin 99 is involved in animal cell separation.
⚈ Collagenase enzyme helps in wound healing by assisting in blood clot formation.
⚈ Transferrins are iron-binding blood plasma glycoproteins that control the level of free iron in biological fluids. Correct Option: B
⚈ Erythropoietin (EPO) is a hormone that prevents anemia (low blood count) by making red blood cells. Anemia causes fatigue and low energy levels. It occurs when there are not enough red blood cells to carry oxygen from the lungs to supply all the body’s needs. Erythropoietin has its primary effect on red blood cells progenitors and precursors by promoting their survival through protecting these cells from apoptosis.
⚈ Anti-fibrin 99 is involved in animal cell separation.
⚈ Collagenase enzyme helps in wound healing by assisting in blood clot formation.
⚈ Transferrins are iron-binding blood plasma glycoproteins that control the level of free iron in biological fluids.
